So far so good. Now let's talk about sugars in foods. Sugars are just simple carbohydrates, but glucose has a non-identical twin – fructose - which is also used as a building block in plant structures. Fructose has the same chemical formula as glucose but the atoms are arranged in a different way. Fructose can't break down to glucose; so fructose has a very low GI. In principle its GI should be zero, but the current GI scale isn't accurate enough to pick that up.
Glucose and Fructose occur naturally in plants. Grape juice is almost totally glucose, whilst agave syrup is almost totally fructose. Honey is a mixture of fructose and glucose. The stuff we put in our tea (table sugar = sucrose) is more complicated. The sucrose molecule is made of one molecule of fructose and one molecule of glucose stuck together. When we eat table sugar it breaks down in our gut very rapidly to its fructose and glucose parts, and only the glucose part ends up in the bloodstream. So the glycemic effect of eating sucrose is about half that of eating glucose. Higher sugars comprise more molecules stuck together and eventually become starches.
Starches are essentially no different from sugars : chemically they're called polysaccharides which just means many sugars stuck together. When we eat starches they also break down to simple sugars and the glucose released can enter the bloodstream just as if you had eaten a simple sugar. The most potent example of this is Cornflakes, which although low in sugars, raises blood glucose levels faster than almost anything else – including table sugar! When you put sugar on Cornflakes you actually REDUCE the amount of glucose that ends up in your bloodstream.
A 50g serving of Lizi's Granola has a GL of 5.5g, which means your blood sugar would have increased AS IF you had eaten 5.5g of glucose. Compare Cornflakes – a 50g serving has a GL of 31g, which means that your blood sugar would have increased AS IF you had eaten 31g
of glucose. We think GL is a crucial piece of information, and only Lizi's granola gives you an accurate GL measure.